Page:Proceedings of the Royal Society of London Vol 60.djvu/339

312 activity in the British Isles from the earliest geological ages to Middle Tertiary times.

In the first series of these papers—commencing with the “ Chronology of the Trap Rocks of Scotland ” (1861), and ending with the “ Tertiary Volcanic Rocks of the British Isles ” (1869), abundant original proofs were advanced of the activity of volcanic action in the Western Isles of Scotland, and of its long duration in geological time. The second series (1871-88) was especially distinguished by the publication of his remarkable paper on the “ Carboniferous Volcanic Rocks in the Basin of the Firth of Forth,” our earliest, and, as yet, our only monograph on a British volcanic area belonging to a pre-Tertiary geological system. The third series (begun in 1888) commenced with his memoir on the “ History of Volcanic Action during the Tertiary Period in the British Isles,” a paper which is by far the most detailed and masterly contribution yet made to the subject, and for which the Brisbane Medal was awarded him by the Royal Society of Edinburgh; and this succession of papers has been followed by the publication of others of almost equal importance.

Sir Archibald Geikie has also written many papers and memoirs bearing upon geological processes and their effects, which have become permanent parts of our scientific literature.

While carrying out this highly important original work in Geology, Sir Archibald has most materially contributed to the advancement and diffusion of scientific knowledge by his many educational works upon Geology and Physical Geography. His ‘ Elementary Lessons on Physical Geography ’ has passed through several English and Foreign editions; his ‘ Outlines of Field Geology’ is now in its fifth edition; and his article on Geology—originally contributed to the ‘ Encyclopaedia Britannica ’ in 1879—was afterwards expanded by him into his well-known ‘ Text-book of Geology,’ which has become the acknowledged British standard of Geology in general.

The other Royal Medal is awarded to Professor Boys, who has given to physical research a method of measuring minute forces far exceeding in exactness any hitherto used, by his invention of the mode of drawing quartz fibres, and by his discovery of their remarkable property of perfect elastic recovery.

Professor Boys has himself made several very important researches in which he has employed these fibres to measure small forces. Using a combination of a thermo-junction with a suspended coil in a galvanometer of the usual D’Arsonval type, a combination first devised by D’Arsonval himself, Professor Boys developed the idea in the micro-